<div class="refentry" lang="en" xml:lang="en"><a id="glPassThrough"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glPassThrough — place a marker in the feedback buffer</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glPassThrough</b>(</code></td><td>GLfloat  </td><td><var class="pdparam">token</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>token</code></em></span></dt><dd><p>
                    Specifies a marker value to be placed in the feedback buffer
                    following a <code class="constant">GL_PASS_THROUGH_TOKEN</code>.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
        </p><p>
            Feedback is a GL render mode.
            The mode is selected by calling
            <a class="citerefentry" href="glRenderMode"><span class="citerefentry"><span class="refentrytitle">glRenderMode</span></span></a> with <code class="constant">GL_FEEDBACK</code>.
            When the GL is in feedback mode,
            no pixels are produced by rasterization.
            Instead,
            information about primitives that would have been rasterized
            is fed back to the application using the GL.
            See the <a class="citerefentry" href="glFeedbackBuffer"><span class="citerefentry"><span class="refentrytitle">glFeedbackBuffer</span></span></a> reference page for a description of the
            feedback buffer and the values in it.
        </p><p>
            <code class="function">glPassThrough</code> inserts a user-defined marker in the feedback buffer
            when it is executed in feedback mode.
            <em class="parameter"><code>token</code></em> is returned as if it were a primitive;
            it is indicated with its own unique identifying value:
            <code class="constant">GL_PASS_THROUGH_TOKEN</code>.
            The order of <code class="function">glPassThrough</code> commands with respect to the specification
            of graphics primitives is maintained.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">glPassThrough</code> is ignored if the GL is not in feedback mode.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glPassThrough</code> is executed between
            the execution of <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding execution of <a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_RENDER_MODE</code>
        </p></div>
        {$pipelinestall}{$examples}
        <div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glFeedbackBuffer"><span class="citerefentry"><span class="refentrytitle">glFeedbackBuffer</span></span></a>,
            <a class="citerefentry" href="glRenderMode"><span class="citerefentry"><span class="refentrytitle">glRenderMode</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><div id="Copyright"><h2>Copyright</h2><p>
            Copyright © 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></div>
